Thermo-oxidative rubber aging is highly dependent on the environmental conditions the rubber has been exposed to versus time. A car that has low mileage, always garaged in reasonable temperatures, etc, will have a dramatically different aging process than one that has higher mileage and therefore many more heat cycles. Similarly, a high mileage car (or even a low mileage one) that has been outside most of its life will have a dramatically different rubber aging outcome (window surrounds, anything exposed to UV, even door seals due to large heat cycling ranges) for rubber components. It's not a simple "it is this old, so they are all the same" outcome -- an assumption like that could not be further from the actual outcome.
One example is the original front tires off my M5 I had in controlled temperature dark storage for more than 13 years I recently posted a thread on. They look as new. Zero dry rot/aging evidence at all. That said, they should never be used for serious driving of course since it's impossible to "know" the interior quality of the rubber-to-belt bonds with this age tire. However, a tire is a much different component with a totally different service profile than a door seal, window surround, rear main seal, CSB cover, etc.
Hence trying to guess the rubber aging on any given car is futile unless you have documented provenance of the car's storage and usage profile versus it's mileage which would include climate conditions.
All that said, on any used car a thorough inspection of many of the mentioned parts, and more, is required. Speaking of thrust arm bushings...those disintegrate LONG before they even had the thought of rubber aging!
The other point is that what needs "replacing" is actually a subjective measure for every owner...take the recent case of a long time board member who drove his M5 to close to 300k miles and then was stranded when the guibo exploded. He took pride in having that component last that long. Many here, myself included, inspect such parts and replace when they are not providing near new service conditions (i.e. any M5 with 50k miles likely needs a new one imo). He would argue you're spending money needlessly (and with a good reason to back that up). Hence the old adage that when you buy a used car, you're especially buying the previous owner applies very strongly. There are actually many owners who follow the belief that "if it's still rolling, everything's fine".